A number of methods for detecting explosives are currently available. At present, the most commonly employed method utilizes the sense of smell of an animal such as a dog, pig, or a pouched rat trained for this purpose. The noses of these animals can detect minute amounts of airborne-explosives molecules that leak from sealed containers, such as mines or bombs.
Another approach to explosives detection is based on mass-spectroscopy of air samples. Although feasible for use outside a laboratory, currently available mass spectrometric systems tend to be an inconvenient size for use in the field.
Another technique relies upon nuclear quadrupole resonance (NQR) signals.
Thus the need exists for a fast, reliable, improved sensor for detecting minute concentrations of air-borne explosive molecules.